Q: We live in Sycamore Canyon, Corona de Tucson area. A local landscaper planted three 24-inch box mastic trees for us in January this year. They looked very healthy at the time of planting. Within a month, the backs of the leaves, on all three trees, had become severely spotted (see photos attached). At that point they had been getting drip irrigation equal to one hour every other day.
When the weather warmed, we increased it to two hours every other day. There has been quite a bit of new growth on all the trees and the new growth looks healthy, but we are concerned that the trees are diseased or infested, though we cannot see any bugs. Can you diagnose this problemΒ ?
A:Β I think itβs likely your trees are suffering from either transplant shock or a weather-related disease. The old growth looks stressed but the new growth looks great. I recommend waiting to see how your trees respond through the spring. Your watering and patience may be enough until the stress of transplanting subsides and they grow through the leaf spot problem. Keep an eye on it to see if the new growth continues to look good or if the damage gets worse. We can always take a closer look at a sample of the leaves if things donβt improve.
Peter L. Warren is the Forest Health Program Coordinator for the Arizona Department of Forestry and Fire Management. Questions, photos or videos may be emailed to
